/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.iotdb.db.queryengine.plan.relational.sql.ast;

import com.google.common.collect.ImmutableList;

import java.util.List;
import java.util.Objects;
import java.util.stream.Collectors;

import static com.google.common.base.MoreObjects.toStringHelper;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.collect.ImmutableList.toImmutableList;
import static java.util.Objects.requireNonNull;

public class GroupingSets extends GroupingElement {

  public enum Type {
    EXPLICIT,
    ROLLUP,
    CUBE
  }

  private final Type type;
  private final List<List<Expression>> sets;

  public GroupingSets(Type type, List<List<Expression>> sets) {
    super(null);
    this.type = requireNonNull(type, "type is null");
    requireNonNull(sets, "sets is null");
    checkArgument(!sets.isEmpty(), "grouping sets cannot be empty");
    this.sets = sets.stream().map(ImmutableList::copyOf).collect(toImmutableList());
  }

  public GroupingSets(NodeLocation location, Type type, List<List<Expression>> sets) {
    super(requireNonNull(location, "location is null"));
    this.type = requireNonNull(type, "type is null");
    requireNonNull(sets, "sets is null");
    checkArgument(!sets.isEmpty(), "grouping sets cannot be empty");
    this.sets = sets.stream().map(ImmutableList::copyOf).collect(toImmutableList());
  }

  public Type getType() {
    return type;
  }

  public List<List<Expression>> getSets() {
    return sets;
  }

  @Override
  public List<Expression> getExpressions() {
    return sets.stream().flatMap(List::stream).collect(Collectors.toList());
  }

  @Override
  protected <R, C> R accept(AstVisitor<R, C> visitor, C context) {
    return visitor.visitGroupingSets(this, context);
  }

  @Override
  public List<Node> getChildren() {
    return ImmutableList.of();
  }

  @Override
  public boolean equals(Object o) {
    if (this == o) {
      return true;
    }
    if (o == null || getClass() != o.getClass()) {
      return false;
    }
    GroupingSets that = (GroupingSets) o;
    return type == that.type && sets.equals(that.sets);
  }

  @Override
  public int hashCode() {
    return Objects.hash(type, sets);
  }

  @Override
  public String toString() {
    return toStringHelper(this).add("type", type).add("sets", sets).toString();
  }

  @Override
  public boolean shallowEquals(Node other) {
    if (!sameClass(this, other)) {
      return false;
    }

    GroupingSets that = (GroupingSets) other;
    return Objects.equals(sets, that.sets) && Objects.equals(type, that.type);
  }
}
